Other cryptocurrencies are not like Bitcoin because they're not Bitcoin. They're different. While Bitcoin is not owned by anybody and is fully open source, meaning anybody could copy it, recreate it, even improve it, the circumstances surrounding Bitcoin make all the difference.
Bitcoin has been copied a number of times already, but look where those copies are today. It seems to me it is all about the incredible level of trust that people have developed toward Bitcoin. Such trust does not solely come from Bitcoin's fundamental features; the circumstances around it truly helped.
Anybody could create another Bitcoin-like cryptocurrency, but it will never gain value more than, or even equal to, Bitcoin simply because of the circumstances.
The decentralization of bitcoin makes it has more value on the market. Decentralization help the network being healthy. Additionally, any upgrade for Bitcoin protocol need to be voted and locked in with high support from the community. It is very different than altcoins or clones of bitcoin, they are centralized and teams behind those projects can centralize protocol, change it in the way they want.
Bitcoin came out as the first truly decentralized currency. It came out as a product of an unknown genius. In other words, it almost came out from nowhere, although, of course it has its precursors. These circumstances probably made Bitcoin more trustworthy.
Copy and use code of bitcoin is easy for coders but later they don't have idea and capacity to develop their clones. Failures of clones are come from incapable developmental ability of their developers.
Bitcoin has a genius found (Satoshi Nakamoto) and a outstanding core team of developers